System and method of controlling a high-discharge comminuting or pulverizing mill,such as a tube mill

ABSTRACT

Method of controlling a high discharge comminuting mill such as a tubular mill which comprises supplying part of a main flow of material to be comminuted in an operating comminuting mill to a control mill located upstream of the operating mill in direction of main flow and having a mode of operation substantially similar to that of the operating mill, comminuting the part of the material flow in the control mill, measuring given physical properties at the control mill for determining technical data necessary for operating the operating mill, transmitting the data to a computer, converting the data in the computer to control values for the operating mill, and transmitting the control values to the operating mill for controlling the latter; and system for carrying out the method.

United States Patent 1131 3,692,247 Jager 1 Sept. 19, 1972 [54] SYSTEM AND METHOD OF 3,179,345 4/1965 Kivert et al. ..24l/30 CONTROLLING A HIGH-DISCHARGE 3,314,614 4/1967 Daniel et al. ..241/30 COMMINUTING OR PULVERIZING MILL, SUCH AS A TUBE MILL Primary Examiner-Granville Y. Custer, Jr.

-' Attomey-Curt M. Avery, Arthur E. \Vilfond, Herbert [721 Heinz EFB Q PF" lllill. .2 L. Lerner and Daniel J. Tick [73] Assignee: Wedag Westfalia Dinnendahl Groppel Aktiengesellschaft, Bochum, [57] ABSTRACT Germany Method of controlling a high discharge comminuting Filed: Nov- 3, 1970 mill such as a tubular mill which comprises supplying [2]] Appl- No; 86 477 part of a main flow of material to be comminuted in an operating comminuting mill to a control mill located upstream of the operating mill in direction of Foreign Application Priority Data main flow and having a mode of operation substan- Nov. 5, 1969 Germany ..P 19 55 569.2 iially Similar to that of the Operating mill, comminuiing the part of the material flow in the control mill, 52 us. or. ..241/30, 241/34, 241/63, measuring given p y Properties at the control mill 241/13 5 for determining technical data necessary for operating [51] Int. Cl ..B02c 17/24 t op a i g mill, transmitting the data to a com- [58] Field or Search ..241/30, 33, 34, 63, 64, 134, puter. converting the data i the mp te o c ntrol 241/135, 137 values for the operating mill, and transmitting the control values to the operating mill for controlling the [56] References Cited latter; and system for carrying out the method.

UNITED STATES PATENTS 2 Claims, 1 Drawing Figure 2,929,878 3/1960 Daniel ..241/34 x m i 2,980,347 4/1961 Claes ..24l/34 l I T QM; il ,1

l 22 l I l l ,2: r I ll 19 21 l .J 7 COMPUTER PATENTEDSEP 19 1972 mwhDnzzou *m 9 t/h (tons per hour) of fine comminuted or pulverized material.

ln comminuting mills with conventional dimensions that have been known heretofore, which have a tubular mill as operating mill, for example, tests have been undertaken during the operation thereof to determine amongst other values the feed quantity, the circulating quantity, the quantity of fine material produced and the grain sizes thereof, the grindability and the incident temperatures, in order to attain an optimum mode of operation of the mills. By means of these measured values, in addition to the control of the test quantity, for example, the filling or batch of the ground bodies is also controlled. Since the result of the variations in the batch of ground bodies can only be redetermined after a given time period by means of the grinding effects or data determined at the particular stage, such a mill control requires considerable time consumption. The larger such mill units become in the future, the more difficult and complex it will be to run in the operating mill to its optimal mode of operation.

. It is an object of the invention to provide method and system of controlling a high discharge mill so that the running-in time thereof is as short as possible.

With the foregoing and other objects in view, there is provided in accordance with the invention, method of controlling a high discharge comminuting mill such as a tubular mill which comprises supplying part of a main flow of material to be comminuted in an operating comminuting mill to a control mill located upstream of the operating mill in direction of main flow and having a mode of operation substantially similar to that of the operating mill comminuting the part of the material flow in the control mill measuring given physical properties at the control mill for determining technical data necessary for operating the operating mill, transmitting the data to a computer, converting the data in the computer to control values for the operating mill, and transmitting the control values to the operating mill for controlling the latter.

In accordance with another aspect of the invention, there is provided a system for performing the foregoing method comprising a control mill located upstream of an operating comminuting mill in direction of a main flow of material to be comminuted in the operating mill, the control mill having a mode of operation substantially similar to that of the operating mill, means for measuring given physical properties at the control mill so as to determine technical data necessary for operating the operating mill, computer means for converting the technical data to control values for the operating mill, first transmitting means for transmitting the technical data to the computer means, and second transmitting means for transmitting the control values from the computer means to the operating mill.

- Technical data that is determined in accordance with the invention are, for example, the feed quantity, the circulating quantity, the quantity of fine material, the grain sizes, temperature, grindability, quantity of water injection, and other.

The operating comminuting mill does not merely determine, as heretofore, the variations in the different technical data but rather, this determination is made exclusively at the control mill so that the operating mill can operate, due to the predetermined values, in optimal range during the continuous operation'thereof.

The installation of a control mill in accordance with the invention provides the additional advantage that, for example, the most suitable filling of grinding balls or the anticipated type of comminutable material, with respect to the strength of stability thereof, can be determined even before start-up of the operating mill by prior tests at'the considerably smaller control mill. This is of special importance where, for example, a new cement factory with rotary kilns is set into operation and where no operational values have been obtained as yet for the grindability and the other properties of the clinker.

Since the testings and determinations of the technical data are the considerably smaller, though similar control mills can be established considerably faster than at the operating mill proper, the latter is capable of being run-in to and maintained at the optimal mode of operation in a much shorter time period. Naturally, a control mill can also be employed for controlling several operating mills that are connected in parallel.

A method of controlling the charging or feeding of a tubular mill is known from the German Pat. 1,053,90l issued Sept. 24, 1959, wherein a relatively small quantity is taken from the material to be comminuted in the tubular mill and is fed to a crushing mill which serves as command or control transmitter for the feeding device of the tubular mill. Such a crushing mill has a different mode of operation, however, than that of the tubular mill located downstream therefrom, and the crushing mill serves also only for controlling the test material.

Other features which are considered as characteristic for the invention are set forth in the appended claims.

Although the invention is illustrated and described herein as system and method of controlling a highdischarge comminuting or pulverizing mill, such as a tube mill, it is nevertheless not intended to be limited to the details shown, since various modifications may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.

The invention, however, together with additional objects and advantages thereof will be best understood from the following description when read in connection with the accompanying single FIGURE of the drawing where there is shown a system for carrying out the method of controlling a high-discharge comminuting mill in accordance with the invention.

Referring now to the drawing, there is shown therein an embodiment of a high discharge pulverizer or comminuter mill according to the invention which is made up of a so-called bucket elevator recycling mill assembled of a tube mill 1, a bucket elevator 2, which receives comminuted material from the tube mill 1 and raises it to a level at which it is reintroduced into a separator 3 from which it is discharged onto a conveyor belt 4 which conveys it to the mill 1.

The material being comminuted or pulverized, such as clinker or gypsum, for example, is supplied from supply bins 23 over conventional metering devices 5 with the aid of a conveyor belt 6 which conveys the 3. supplied material to the inlet to the tube mill 1. Upstream of the tube mill 1, a system which includes a control mill 7 is located. The control mill 7 is continuously supplied with test specimens or samples taken from the conveyor belt 6. The test specimens are precomminuted in a pre-comminuting device 8 of conventional construction, and then passed through a screen or sieve 9, the material passing through the sieve 9 being then delivered to a supply bin 15. The material supplied from the supply bin 15 is conducted through a conventional metering device 10 to the control mill 7. Excess material delivered to the supply bin is returned by a bucket elevator 16 to the conveyor belt 6. The control mill 7 cooperates with a separator 11,

that is coordinated therewith through a recycling bucket elevator 12 in a secondary circuit. Coarse material from the separator 11 is returned to the control mill by a conveyor belt 13 having a builtin belt scale 14. Suitable sensing and measuring devices shown -'collectively and diagrammatically at 18, are provided at the control mill for determining the quantity of cycling material, the supply quantity, the quantity of finely ground material and other values. Test samples are automatically taken alternately from a part of the fine material flow out of the separator 11 as well as out of the separator 3 and are tested in a conventional testing apparatus 17 as to grain sizes, toughness, grindability, Blain value and the like, and compared to one another. All the values determined in the control mill by the devices 18, such as the quantity of cycling material, the supply quantity, the quantity of finely ground material and the like, and the fine details determined in the testing device 17 are fed by respective transmission lines 19 and 20, to a computer 21 which is in turn connected to conventional devices at the tubular mill 1, shown collectively at 22 for controlling the operation of the tube mill 1 with respect to the deter mined data in accordance with the given nominal values.

lclaim:

1. Method of controlling a high discharge comminuting mill such as a tubular mill which comprises supplying part of amain flow of material to be comminuted in an operating comminuting mill to a control mill located upstream of the operating mill in direction of main flow and having a mode of operation substantially similar to that of the operating mill, comminuting the part of the material flow in the control mill, measuring given physical properties at the control mill for determining technical data necessary for operating the operating mill, transmitting the data to a computer, converting the data in the computer to control values for the operating mill, and transmitting the control values to the operating mill for controlling the latter.

2. Apparatus for performing a method of controlling a high discharge comminuting mill, comprising a control mill located upstream of an operating comminuting mill in direction of a main flow of material to be comminuted in the operating mill, said control mill having a mode of operation substantially similar to that of the operating mill, means for measuring given physical properties at said control mill so as to determine technical data necessary for operating the operating mill, computer means for converting said technical data to control values for the operating mjll, first transmitting means for transmitting said technical data to said computer means, and second transmitting means for transmitting said control values from said computer means to the operating mill.

* l I I! 

2. Apparatus for performing a method of controlling a high discharge comminuting mill, comprising a control mill located upstream of an operating comminuting mill in direction of a main flow of material to be comminuted in the operating mill, said control mill having a mode of operation substantially similar to that of the operating mill, means for measuring given physical properties at said control mill so as to determine technical data necessary for operating the operating mill, computer means for converting said technical data to control values for the operating mill, first transmitting means for transmitting said technical data to said computer means, and second transmitting means for transmitting said control values from said computer means to the operating mill. 